diff --git a/doc/develop/tests_writing.rst b/doc/develop/tests_writing.rst
index a328ebf..54efb7e 100644
--- a/doc/develop/tests_writing.rst
+++ b/doc/develop/tests_writing.rst
@@ -321,15 +321,15 @@
 Finally, add the test to the build by adding to the Makefile in the same
 directory::
 
-  obj-$(CONFIG_$(SPL_)CMDLINE) += wibble.o
+  obj-$(CONFIG_$(XPL_)CMDLINE) += wibble.o
 
 Note that CMDLINE is never enabled in SPL, so this test will only be present in
 U-Boot proper. See below for how to do SPL tests.
 
 As before, you can add an extra Kconfig check if needed::
 
-  ifneq ($(CONFIG_$(SPL_)WIBBLE),)
-  obj-$(CONFIG_$(SPL_)CMDLINE) += wibble.o
+  ifneq ($(CONFIG_$(XPL_)WIBBLE),)
+  obj-$(CONFIG_$(XPL_)CMDLINE) += wibble.o
   endif